I'll help you fix this issue so you can preview the details on your Expense Voucher in QuickBooks Online (QBO).
Did you get some error messages? Any additional information will help me provide the best resolution for your concern.
In the meantime, let's sign in to your QBO using a private browser (incognito). There are times that the browser is already full of frequently accessed page resources (cache and cookies), causing some unusual responses. Here's how:
Press Ctrl + Shift + N (Google Chrome).
Ctrl + Shift + P (Firefox).
Control + Option + P (Safari).
Ctrl + Shift + P (Microsoft Edge)
Once logged in, try to print the Expense Voucher again to double-check. If it successful, return to your default browser and perform a clear cache to refresh the system. However, if the issue persists, try using other supported browsers.